http://bugs.gentoo.org/show_bug.cgi?id=80345

diff -uNr shadow-4.0.7.orig/src/su.c shadow-4.0.7/src/su.c
--- shadow-4.0.7.orig/src/su.c	2005-02-01 12:22:11.553956864 +0100
+++ shadow-4.0.7/src/su.c	2005-02-01 12:22:33.077684760 +0100
@@ -111,7 +111,7 @@
 {
 	struct group *grp;
 
-	grp = getgrgid (0);
+	grp = getgrnam ("wheel");
 	if (!grp || !grp->gr_mem)
 		return 0;
 	return is_on_list (grp->gr_mem, username);